HI, The problem is with the revs of my dads car, a 1999 v6, never been abused at all.... when the car is on idle the revs are right under 1000 which is normal, because i have a 2000 v6 that is under 1000 as well, but the problem with my dads is that sometimes his revs go up to 1500 for like three days, and then it comes back down... could a sensor be bad??? Thanks